Apparatus for manufacturing concrete blocks and the like



L. J- ESTIS APPARATUS FOR MANUFACTURING CONCRETE BLOCKS AND LIKE Filed Jan. 10, 1968 2 Sheets-Sheet l INV ENT OR jo/w/z {1374a ryf fnoRNs May 26, 1970 L. J. ESTIS 5 5 APPARATUSJOR MANUFACTURING CONCRETE BLOCKS AND THE LIKE I I Filed Jan. 10, 1968 v 2 Sheets-Sheet 2 IN VEN TOR j/wv/ls [5770- ATTORNEY BY Faafer J $7 .12

United States Patent 'ice Int. Cl. B28b 13/02 U.S. CI. 25-41 2 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates to apparatus for manufacturing concrete blocks which comprise a hopper for the material to be stored in before being delivered to moulds ..(material being cement, aggregate and water); moulds for forming the individual blocks; and a feed box assembly which receives the material from the discharge opening of the hopper, which is usually adjacent the rear of the block manufacturing machine and, transfers it to a position from which it falls into .the mould boxes there- :below; said feed box assembly possessing an agitator grid, made up of a framework'with horizontally disposed bars wtih prongs extending downwardly therefrom.

The present invention provides means for preventing the accumulation, in concrete block machines, of hardened jconcrete on the aforementioned parallel grid bars and transversely extending cross-bars and prongs of the agitator grid; Said means comprisinga series of metallic rings whichare. carri d ,bythe gridbars' and which are sufliciently loose thereon to rattle in the same plane as the direction of agitation of the agitator grid, and at the same time slip sideways sufficiently toruhagainst the other members of the agitator grid assembly.

The accumulation pfi- -hardenedconcrete mix on the agitator grid, including cross bars'and prongs, ishighl-y undesirable, as the accumulated hardened material ocoupies space which would otherwise permit concrete mix to pass therethrough into the mould boxes. If not somehow eliminated, the accumulated hardened cementitious material results in a lesser quantity of mix being received into the mould cavities, which are fed thereby, thus producing concrete blocks which are not uniform and which are of generally inferior quality, as will be explained shortly hereinafter.

This condition, if permitted to persist, becomes increasingly more aggravated with the duration of the run, or period of operation of the concrete block apparatus; the blocks produced at the end of a days run being of a different density than those whch were produced at the beginning thereof, due entirely to the gradual buildup of the' hardened concrete mix on the agitator grid.

In addition to the objectionable differences in the rate of flo-W of the concrete mix from the agitator feed box assembly into the mould boxes and the resultant difference in the density and quality of the concrete blocks being molded, the accumulation described results in impairment of strength and texture of the block itself.

As previously indicated, the primary object of the present invention is to eliminate the building-up or accumulation of hardened concrete mix around the parallel horizontally disposed grid bars and the transversely extending cross-bars and prongs of the agitator grid, and thereby enable the production of concrete blocks which are of approximately the same density, strength and texture throughout the operation of the concrete block apparatus or machine.

Another object is the attainment of the foregoing by instrumentalities which are inexpensive and durable in service; and which may be easily and rapidly installed in concrete block machines which are already in service.

, 3,513,513 Patented May 26, 1970 These, together with other objects and advantages which will become subsequently apparent, reside in the elements as more fully hereinafter described and claimed.

Referring to the attached drawings:

FIG. 1 is a perspective of a' more or less conventional concrete block machine of the type to which the present invention is applicable; 1

FIG. 2 is a perspective of a conventional agitator feed box assembly which forms part of a concrete block machine of the type shown in FIG. 1;

FIG. 3 is a perspective of the grid support bar assembly which forms part of the agitator feed box assembly of FIG. 2;

FIG. 4 is a perspective of the grid support bar assembly of FIG. 3 as provided with an agitator grid which embodies the teachings of the present invention;

FIG. 5, is a perspective illustrating the agitator grid and associated instrumentalities as removed from the grid support bar assembly of FIG. 3;

FIG. 6 is an elevational view which shows the improved agitator grid in place, and with the stripper head assembly and its stripper shoes in position to move downwardly and press the concrete mix into the moulds after the feed box is moved backwardly toward the rear of the machine; and

FIG. 7 is a fragmentary perspective which illustrates more clearly the structure of the improved agitator grid of the invention.

Referring more particularly to the drawings, the numeral 1 designates the mixed material hopper of a more or less conventional concrete block machine which is supplied, in any suitable manner such as a skip hoist, with a preliminarily mixed composition of cement, aggregate oraggregates, and water and/or other additives.

The concrete mix flows downwardly through the discharge opening of the mixed material hopper (which is usually adjacent the rear of the concrete block machine) and into the feed box of an agitator feed box assembly 2.

:The aforementioned feed box comprises a rectangular or box-like frame with open top and bottom which rests upon a smooth horizontal plate. This smooth horizontally disposed plate extends from immediately below the discharge opening of the mixed material hopper to a position which is just short of being above the mould box.

This agitator feed box assembly 2 transfers the concrete mix from the rear of the cement block machine to the front thereof, Where the mould box is located. After agitating the concrete mix and depositing it in the moulds, the agitator feed box withdraws to the rear of the machine, and the'deposited concrete mix is pressed into the mould box while the latter is vibrated; :all in the manner well known in the art.

As shown in FIGS. 2 and 4, the agitator feed box assembly 2 comprises a grid support bar assembly 3 formed 'of a pair of spaced, parallel longitudinal bars 5 which are secured in position by one or more crossrods 7.

Disposed upon and extending between the parallel longitudinal bars 5 of the grid support bar assembly 3 is an agitator or shaker grid 10, the latter comprising a pair of spaced, parallel longitudinally extending bars 12 and a series of spaced, parallel transversely extending bars 14 which extend between and are'connected to the longitudinally extending bars 12.

As will be observed, each of the spaced, parallel transversely extending bars 14 is provided with a series of appropriately spaced, depending prongs 16 which may be tapered or untapered, and of any desired cross-section, including rectangular, triangular, round, etc.

When the agitator feed box of the agitator feed box assembly 2 is over the moulds, the agitator or shaker grid 10 causes an even distribution of the concrete mix into The concrete mix itself is of a semi-dry consistency and somewhat gummy, and while the downwardly depending prongs 1-5 have a pronounced stirring effect, the concrete mix builds up around the transversely extending bars 14 and the downwardly depending prongs to the point where efii-eiency is greatly impaired. v

' According to the present invention, the transversely extending bars 14 of the agitator or shaker grid 8 are provided with one or more loosely disposed rings'20 on the portions thereof which are between adjacent pairs of downwardly depending prongs 16 and/or adjacent to the longitudinally extending bars 1'2, the said rings being mounted with sutficient looseness to permit them to rattle in the same plane as the direction of the agitation of the grid, and at the same time capable of slipping sidewise into rubbing contact with the adjacent surface or side of the most adjacent downawrdly depending prong and extending ,arms 12.

' The advantages of providing the rings 20 in the position and manner described, and thereby eliminating the objectionable build-up of the concrete mix, include:

Enabling a more uniform flow of concrete mix into the mould cavities;

Eliminating the necessity of having to remove concrete build-up on the grids at the end of a run or at intervals during a run;

The production of a more uniform product. Since the compressive strength in a concrete block is a most important quality, it follows that the amount of material compressed into a mould cavity determines the density and ultimate strength of the concrete block;

Uniformly of density, weight and texture of concrete blocks throughout the period of operation of the concrete block machine;

Savings in the amount of cement required to produce a concrete block of a given compressive strength require ment, since concrete blocks produced with less concrete 7 thus eliminating the necessity of an excessive amount of cement for blocks of less density caused by less, or an uneven amount of matcrialbeing placed in the. moulds.

While I have shown and described certain specific embodiments of the present invention, it will be readily understood by those skilled in the art that I do not wish to be limited exactly thereto, since various modifications may be made without departing from the scope of the invention as defined in the appended claims.

1. The combination of a concrete block machine, including hopper, mould boxes, and'an agitator feed box assembly adapted to receive concrete mix from the hopper andtransfer the same to the mould boxes, with an agitator grid carried said agitator feed box assembly; said agitator grid comprising a pair of longitudinally extending members and a plurality of transversely extending bars having a series of spaced, downwardly depending prongs, and at least one ring loosely carried'by each of said transversely extending bars on that portion thereof which extends, between the downwardly depending prongs and/or'adjacent to pair of: extending members; said rings being of such size and shape as to permit their rattling in the same plane as'the' direction of the agitational or oscillatory movement of the agitator grid.

2. The apparatus of claim 1 wherein the rings are capable of slipping sidewise into rubbing contact with the most adjacent downwardly depending prong and/or the longitudinally extending members'of the agitator grid.

I iRefere n c es Cited r v UNITED, STATES'PATENTS i/l942 Wellnitz 2s 41 x 2,652,613- 9/1953 Warren -51---. 25'103 X 2,801,773 8/1957 Vitkin 222200 2,958,917 11/1960 Harris 2541 J. SPENCER OVERI- IOL SE R, Primary Examiner B, D; TOBQR, Assistant Examiner 

